Trypanosoma cruzi populations : more clonal than sexual

Abstract

The ancient guestion of trypanosome sexuality has recently been reactivated in view of important observations in the African species Trypanosoma brucie, in which Mendelian sexuality has been proposed as o working hypothesis on the basis of indirect isozyme evidencer. Subsequent experiments have confirmed that recombination can occur in T. brucei under defined experimental conditions and suggest that this parasite undergoes meiosis2-4. ln this article, Michel Tbayrenc and Francisco Ayalo discuss the intraspecific variability of another species, Trypanosoma cruzi - causative agent of american trypanosomiasis or Chagas disease. They interpret the variation revealed by extensive isozyme analysis and restriction endonuclease analysis of kinetoplast DNA, to suggest that T. cruzi is diploid, genetically very polymorphic, and has a clonal structure that manifest a lack of (or very restricted) sexuality.